If you want to be a dog trainer you need to obedience train and title at least one dog. Most people won't take you real seriously without your having direct hands on experience. Once you get involved in a training facility or club, you can generally start helping out with classes and actually working.

If you go to infodog (I think, don't have a direct link) there should be listings of training seminars, club shows, obedience trials, like that. Get involved!

Also start reading dog books (and look for seminars by the authors.) Jean Donaldson is a MUST (especially Culture Clash), Pat Miller (one of my dogs & I are photographed in her newest book!), Ian Dunbar, Suzanne Clothier, Patricia McConnell...and look for seminars & workshops given by these authors, too.
Here's a great link for dog books - you can at least browse:http://www.dogwise.com/